1. Field of the Invention
The present invention relates to a chucking apparatus for a disk player, and more particularly to the chucking apparatus for holding a disk placed on a turn table of the disk player.
2. Description of the Related Art
There have been already proposed chucking apparatuses for holding a disk placed on a turn table of a disk player which are disclosed in Japanese Publications Nos. JP-A-10-228698 and JP-A-6-215461 of unexamined patent applications. In these chucking apparatuses, there are provided a chuck disk and a chuck arm. The chuck disk is a disc-like member which has a locking portion to be locked with the turn table, on its one face. The chuck arm is provided with an opening, and the chuck disk is rotatably disposed inside an inner periphery of this opening.
In these apparatuses, the disk can be held by placing the disk on the turn table and locking the locking portion of the chuck disk with the turn table. The chuck disk rotates integrally with the turn table in a state where the disk is held between the turn table and the chuck disk.
Generally, in case of assembling the chucking apparatus of this type, firstly, the locking portion of the chuck disk is passed along the inner periphery of the opening and positioned at the turn table side. On this occasion, the chuck disk is abutted against an edge of the opening at an outer circumference of its disc-like part, thus preventing an escape of the chuck disk from the chuck arm toward the turn table. Then, a separate member is attached to the chuck arm so as to cover the outer circumference of the chuck disk. This will also restrain an escape of the chuck disk from the chuck arm toward an opposite side of the turn table.
In the conventional chucking apparatuses, it has been necessary to conduct a work for attaching the separate member to the chuck arm, after the chuck disk has been inserted into the chuck arm.
In order to assemble the apparatus in a more simple manner, it has been considered that the chuck arm and the separate member are integrally formed to provide a holding part for holding the chuck disk, and an insertion opening for inserting the chuck disk is formed in the holding part.
When assembling such an apparatus, the chuck disk is inserted from the turn table side contrarily to the conventional assembling manner. In case where such a structure has been employed, it has been necessary to provide, at a plurality of positions on the edge of the opening, retaining projections whose distal ends extend up to slightly inner positions in a radial direction than the outer diameter of the chuck disk in order to prevent the escape of the chuck disk from the insertion opening and, at the same time, to allow the chuck disk to easily pass through the insertion opening.
However, in such a structure, in order to facilitate the work for installing the chuck disk in the holding part, an inwardly projected amount of the retaining projections is limited. In other words, sufficient length of the projections to catch the chuck disk cannot be ensured. Therefore, in some cases, the chuck disk may fall from the holding part, because the chuck disk may push the projections due to vibrations or so during transportation, and the projections may be deformed.
An object of the invention is to provide a chucking apparatus which can be easily assembled, and in which an escape of a chuck disk from a chuck arm can be prevented.
According to a first aspect of the invention, there is provided a chucking apparatus for holding a disk placed on a turn table of a disk player, including a chuck disk and a chuck arm. The chuck disk is a disk having a disc-like shape which can be locked with a turn table. The chuck arm has an opening through which the chuck disk can be inserted, and includes a holding part in which the chuck disk is rotatably arranged, a plurality of first hooks projecting inwardly in a radial direction from an edge of the opening, and at least one second hook provided at the edge of the opening for preventing the chuck disk in the holding part from escaping outward.
The plurality of the first hooks allow the chuck disk to be inserted into the holding part and support the chuck disk in the holding part. The second hook has such a shape that it has higher rigidity with respect to a force received when the chuck disk tends to escape from the holding part as compared with rigidity with respect to a force received when the chuck disk is installed.
When assembling this apparatus, the chuck disk is installed in the holding part through the opening. On this occasion, the plurality of the first hooks are in such an arrangement and a shape that the chuck disk can be passed through the opening. On the other hand, the second hook is pushed by the chuck disk and elastically deformed. However, because the second hook has relatively low rigidity with respect to a force received at this installation, it can be easily deformed elastically. Therefore, the chuck disk can be easily installed in the holding part.
In the chucking apparatus which has been thus assembled, after the disk is placed on the turn table, the chuck disk is locked with the turn table to hold the disk. The chuck disk rotates integrally with the turn table in a state where the disk is held between the chuck disk and the turn table.
In some cases, the chuck arm may be subjected to a force in an axial direction due to vibrations or a shock during transportation or so. In such cases, when the chuck disk tends to escape from the holding part, the outer circumference of the chuck disk interferes with the second hook. However, the second hook has relatively high rigidity with respect to a force received when the chuck disk tends to escape from the holding part, and accordingly, is hard to be elastically deformed. Therefore, the escape of the chuck disk from the holding part can be restrained.
In the chucking apparatus according to a second aspect of the invention, the second hook has higher rigidity in an axial direction of the chuck disk as compared with rigidity in a radial direction of the chuck disk.
In this apparatus, in case of installing the chuck disk in the chuck arm, the chuck disk passes through the opening of the holding part while the second hook is elastically deformed in a radial direction. On this occasion, because the second hook has relatively low rigidity in a radial direction, the second hook is easily deformed elastically when it has received a force in a radial direction when the chuck disk is installed. This facilitates installation of the chuck disk. On the other hand, the second hook has relatively high rigidity in an axial direction, and is hard to be deformed elastically in this direction. Accordingly, when the chuck disk tends to escape from the holding part exerting a force in the axial direction on the second hook, the second hook will not be easily deformed elastically, and thus, prevents the chuck disk from escaping from the holding part.
In the chucking apparatus according to a third aspect of the invention, the second hook is formed in a U-shape extending from the edge of the opening in the chuck arm toward an opposite side to the holding part, folded back toward an inner periphery of the opening, and extending toward the holding part.
In this apparatus, in case of installing the chuck disk in the chuck arm, since the second hook is formed in a U-shape, a distal end of the second hook is easily deformed elastically in a radial direction when the chuck disk passes through the insertion opening, and hard to be elastically deformed in an axial direction. Therefore, the work for installing the chuck disk in the holding part will be easily conducted, and the escape of the chuck disk from the holding part can be restrained.
In the chucking apparatus according to a fourth aspect of the invention, the distal end of the second hook is positioned more inwardly in a radial direction than distal ends of the first hooks.
In this apparatus, because the distal end of the second hook is positioned more inwardly in a radial direction than the distal ends of the first hooks, the escape of the chuck disk from the holding part can be more reliably restrained.